There are many things
you can do now to fight spam and UCE. Show your support for
Pending
Legislation to outlaw spam by writing/calling your
representatives in government. Encourage law enforcement officials
to enforce already enacted anti-spam legislation.

Adopt and enforce
a spam and UCE policy and publish your policy so that your
clients and potential clients are aware of it. Many good spam
and UCE policies can be found here:

sendmail
Resources
Blocking spam is now easier than ever on your Virtual Server.
New methods have been implemented in the newest version of
sendmail to help fight spam. In addition to new features,
the default sendmail configuration continues to support the
same anti-spam features supported previously.